Nonaqueous electrolyte batteries in which charging and discharging are performed when lithium ions move between a negative electrode and a positive electrode have been actively studied as high-energy-density secondary batteries.
In addition to applications as a power supply for a small electronic device, nonaqueous electrolyte batteries are also expected to be used as a medium and large power supply for automotive applications and stationary applications. Life characteristics and high safety are required for such medium and large applications. Furthermore, charging and discharging characteristics under a high-temperature or low-temperature environment are also required.
It is required that oxidation and reductive decomposition do not proceed for a nonaqueous electrolyte used for a nonaqueous electrolyte battery which has excellent life characteristics and charging and discharging characteristics under high-temperature or low-temperature environments. As a method of preventing oxidation of a nonaqueous electrolyte, an electrolyte solvent may be changed to a solvent of which hardly any decomposes at a high potential. In addition, in order to prevent reductive decomposition, an additive such as vinylene carbonate (VC) may be included. Furthermore, as a method of preventing decomposition of a nonaqueous electrolyte under a high-temperature environment, a method of forming a species on a surface of a positive electrode is known.